Tense-Suffixes.—The tense-suffixes, which are added to the verb-stem to form the tense-stems, consist of the thematic vowel and certain other letters. No tense-suffixes are added to the verb-stem (1) in the second aorist active and middle, and second perfect and pluperfect, of μι-verbs; (2) in the perfect and pluperfect middle of verbs in -ω and -μι. The tense-suffixes are as follows:—
1. Present system, -όε-, -τόε-, -yόε-, -νόε-, -ανόε-, -νεόε-, -να-, -νυ-, - (ι) σκόε; or none, as in φα-μέν.
2. Future system, -σόε-.
3. First aorist sytem, -σα-.
4. Second aorist system, -όε-; or none, as in ἔ-στη-ν.
5. First perfect system, -κα- (plupf. -κη- from -κεα-; -κει- from -κεε-; -κε-).
6. Second perfect system, -α- (plupf. -η-, -ει-, or -ε-); or none, as in ἕ-στα-τε.
7. Perfect middle system, none (future perfect -σόε-).
8. First passive system, θη-, -θε- (future passive -θησόε-).
9. Second passive system, η, -ε- (future passive -ησόε-).
N.—-α in the aorist is properly a relic of the personal ending ( cross666).455D 456
Thematic Vowel.—The thematic, or variable, vowel appears at the end of the tense-stems in the present, imperfect, and second aorist active and
middle of ω-verbs, and in all futures and future perfects. The thematic vowel in the indicative is ο before μ or ν (and in the optative of the tenses mentioned); elsewhere it is ε. Thus, λυ_όε-, λιπόε-, λυ_σόε-, λυθησόε-, λελυ_σόε-; λύ_ο-ι_-μι. In the subjunctive it is ώη.
a. Attic inscriptions have both -εσθων and -οσθων in the imperative.457
Subjunctive.—In the subjunctive of all verbs the thematic vowel is ώη-. Thus, λύ_ω-μεν, λύ_η-τε, λύ_σω-μεν, στείλη-τε.
a. Verbs in -νυ_μι form their subjunctive like ω-verbs.457D
Hom. has -όε- instead of -ώη-, especially in the 1 aor., 2 aor. of μι- verbs, and 2 aor. pass. (ἐρύσσομεν, δώομεν, τραπείομεν; also in ἴομεν, εἴδομεν). These forms do not occur in the sing. or 3 pl. active. Verbs in ω rarely show this όε in the present. (Other examples 532, 667 D., 682 D.)458
In the present and second aorist of μι-verbs, and in the aorist passive, ώη is added to the tense stem. Thus τιθῶμεν from τιθέ-ω-μεν, θῶ from θέ-ω, τιθῆτε from τιθέ-η-τε, λυθῶ from λυθέ-ω.459
Suffix of the Optative.—The optative adds the mood suffix -ι_-, or -ιη- which contracts with the final vowel of the tense-stem: λύ_οιμι for λύ_ο-ι_-μι, φιλοίην for φιλεο-ίη-ν, τιθείην for τιθε-ίη-ν. -ιη- occurs only before active endings. When the suffix is -ιη-, the 1 pers. sing. ends in -ν; as τι_μαο-ίη-ν τι_μῴην; when it is -ι_-, the 1 pers. sing. ends in -μι, as τι_μάο-ι_-μι τι_μῷμι.460
ιη is used as follows (in all other cases -ι_-):—
a. In contracted verbs in the singular, rarely in the dual and plural. -ι_- appears in the dual and plural, rarely in the singular.
b. In liquid verbs in the future active singular: φανοίη-ν for φανεο-ίη-ν. In the dual and plural -ι_-: φανοῖτον, φανοῖμεν for φανεό-ι_-τον, φανεό-ι_-μεν.
c. In the singular of μι-verbs: τιθείην for τιθε-ίη-ν, διδοίην for διδο-ίη-ν, θείην for θε-ίη-ν. Here the modal sign is added to the tense-stem without any thematic vowel. -ι_- is more common in the dual and plural: τιθεῖμεν for τιθέ-ι_-μεν, διδοῖμεν for διδό-ι_-μεν, θεῖτε for θέ-ι_-τε. Verbs in -νυ_μι make their optatives like λύ_ω.
d. In the aorist passive: λυθείην for λυθε-ίη-ν, φανείην for φανε-ίη-ν. In the dual and plural -ι_- is more common: λυθεῖμεν for λυθέ-ι_-μεν, φανεῖτε for φανέ-ι_-τε.
e. In some second perfects, as προεληλυθοίης, and in the second aorist σχοίην from ἔχω (but -σχοῖμι in composition).
N.—In the 3 pl. -ιε- is regular before -ν: λύ_ο-ιε-ν, τιθε-ῖε-ν, λυθε-ῖε-ν.460D
-ιη- is very rare in Hom. in the dual and plural.461
a. In the 1 aor. opt. act. of ω-verbs the endings -ειας, -ειε, and -ειαν are more common than -αις, -αι, -αιεν.
b. In the aor. opt. passive of all verbs and in the opt. of μι-verbs and of contract verbs -ιτον, -ιτην, -ιμεν, -ιτε, -ιεν are commoner than -ιητον, -ιητην, -ιημεν, -ιητε, -ιησαν. Prose writers use either the shorter or the longer forms; poets use only the shorter forms. Except in contract verbs -ιητε is very common in the 2 pl. and is sometimes the only form in the Mss., as δοίητε, θείητε, γνοίητε, -βαίητε, λυθείητε, φανείητε; but the forms in question occur in prose writers and their genuineness is therefore unsupported by metrical evidence.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].